The Resource Timing and duration of zeranol treatment in a castrated lamb model : effect on bone mineralization, by Florence Fungai Chanetsa

Timing and duration of zeranol treatment in a castrated lamb model : effect on bone mineralization, by Florence Fungai Chanetsa

Label
Timing and duration of zeranol treatment in a castrated lamb model : effect on bone mineralization
Title
Timing and duration of zeranol treatment in a castrated lamb model
Title remainder
effect on bone mineralization
Statement of responsibility
by Florence Fungai Chanetsa
Title variation
Zeranol effect on bone in castrated lamb
Creator
Subject
Language
eng
Summary
A castrated lamb model was used to study the effect of timing, duration and possible mechanisms through which zeranol (an estrogen agonist) mediates longitudinal bone growth and mineralization in a series of two studies. In Study I, a total of sixty-six wether lambs were assigned to treatment groups during the first two weeks of life (day 0) and then reared on their natural dams until weaning at experimental day 60. Lambs were implanted with 12 mg of zeranol, on experimental day 0 (E-0), day 45 (E-45) and day 90 (E-90). E-0 was reimplanted at day 45 and 90 and E-45 was reimplanted at day 90. Two groups of lambs served as controls to account for temporal changes (C-AGE; i.e. a fixed time) and developmental differences associated with the use of zeranol (C-WT; i.e. a fixed weight). C-WT was fed until the average weight equaled the mean final weight of the heaviest zeranol treated group at day 135. In Study II, forty castrated male lambs were randomized to four groups: (1) age matched control (C-AGE), (2) implanted at birth (12.5 mg zeranol) and reimplanted at day 45, 90 and 135 (E-0), (3) implanted at birth and reimplanted at day 90 and 135 (E-0,90) and (4) implanted at 90 and 135 days (E-90). Body composition (bone mineral density, bone mineral content, lean mass and fat) by dual energy x-ray absorptiometry and extensive blood sampling (to assess markers of bone formation and resorption) were conducted at day 28, 73, 118, 135 and 163 after venous blood samples were collected for measurement of growth hormone, insulin-like growth factor-1, serum minerals, vitamin D and markers of bone turnover. Fractional calcium absorption studies (using $\sp{47}$Ca) was conducted at, 100 and 150 days in 20 of the 40 lambs. Results of study I suggested a direct effect of estrogen treatment on bone turnover and indirect effect via GH and IGF-1 that occurs at a set point during the period of prepuberty. Estrogen treatment from birth appeared to attenuate the growth response. Results of study II suggested that treatment from birth appears to enhance primarily longitudinal growth, whereas later treatment appears to augment primarily bone mineralization. Effects of zeranol on calcium absorption were inconclusive, however there was a suggestion of independent effects of zeranol. Zeranol appears to increase longitudinal growth and bone mineralization by directly acting on bone. Further studies are needed to confirm these effects and to delineate the mechanism
Additional physical form
Also available on the Internet.
Cataloging source
MUU
http://library.link/vocab/creatorDate
1961-
http://library.link/vocab/creatorName
Chanetsa, Florence Fungai
Degree
Ph. D.
Dissertation year
1997.
Government publication
government publication of a state province territory dependency etc
Granting institution
University of Missouri-Columbia
Index
no index present
Literary form
non fiction
Nature of contents
  • bibliography
  • theses
http://library.link/vocab/subjectName
  • Zeranol
  • Bones
  • Biomineralization
  • Osteoporosis
  • Lambs
Target audience
specialized
Label
Timing and duration of zeranol treatment in a castrated lamb model : effect on bone mineralization, by Florence Fungai Chanetsa
Instantiates
Publication
Note
  • Typescript
  • Vita
Bibliography note
Includes bibliographical references (leaves 171-201)
Carrier category
online resource
Carrier category code
  • cr
Carrier MARC source
rdacarrier
Color
not applicable
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent
Control code
41633253
Dimensions
29 cm
Extent
xii, 202 leaves
Media category
computer
Media MARC source
rdamedia
Media type code
  • c
Specific material designation
remote
Label
Timing and duration of zeranol treatment in a castrated lamb model : effect on bone mineralization, by Florence Fungai Chanetsa
Publication
Note
  • Typescript
  • Vita
Bibliography note
Includes bibliographical references (leaves 171-201)
Carrier category
online resource
Carrier category code
  • cr
Carrier MARC source
rdacarrier
Color
not applicable
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent
Control code
41633253
Dimensions
29 cm
Extent
xii, 202 leaves
Media category
computer
Media MARC source
rdamedia
Media type code
  • c
Specific material designation
remote

Library Locations

    • University of Missouri Libraries DepositoryBorrow it
      2908 Lemone Blvd, Columbia, MO, 65211, US
      38.919360 -92.291620
Processing Feedback ...